The present invention relates to an apparatus for releasing telescopic drive spindles from roll necks of a rolling mill and connecting the same thereto, more particularly to an apparatus by which fitting yokes of telescopic drive spindles including universal joints and provided between studs of a stationary pinion stand and the roll necks of the rolling mill can be released from and connected to the roll necks of the rolling mill.
Generally, working rolls of a rolling mill are replaced with the use of a crane by which the roll is moved as suspended therefrom, or with the use of hydraulic means. In the former method, a C-shaped hook or porter bar is usually used. In recent years, a pair of upper and lower rolls are released from or connected to the drive spindles at the same time with the use of a double-eye C-shaped hook or porter bar in order to shorten the work time.
When the pair of upper and lower working rolls are handled at the same time, couplings or yokes of the upper and lower universal joints for the necks of the upper and lower rolls must be held at the same center-to-center spacing as the upper and lower rolls, whereas it is extremely difficult to maintain the upper and lower rolls at definite levels especially when a crane is used.
It is further noted that torque transmission between the coupling or yoke and the roll is effected through a joint including a key or a portion of oval rectangular cross section fitting in a bore of corresponding shape. If there is a relative angular displacement between the coupling and the roll to be jointed thereto, it is extremely difficult to eliminate such angular displacement to fit them together, because the roll neck is supported by a C-hook or porter bar and is not rotatable.
Because of these difficulties, the insertion of the roll neck into the coupling gives a high impact load to the pinion stand, permitting the roll neck to strike the coupling when the corresponding portions to be joined together differ greatly in the above-mentioned spacing or involve a rotational angular displacement.
The spindle carrier disclosed in U.S. Pat. No. 2,815,690 is for use in drive spindles having gear-type couplings of the construction shown by U.S. Pat. No. 2,136,947. The spindle carrier according to U.S. Pat. No. 2,815,690 is so constructed that coupling sleeves engaged with roll necks of a rolling mill are supported from below by cradle pads. Consequently, it is a complicated and troublesome operation on the part of an operator to support simultaneously the coupling sleeves engaged with the roll necks of the upper and lower rolls by the position adjustment of the cradle pads. This is also true of the operation of engaging the coupling sleeves with the roll necks of newly furnished rolls.
With rolling mills, the upper and lower working rolls are replaced with the upper roll placed on the lower roll in intimate contact therewith. When new upper and lower working rolls are installed on the lower backup roll, the center of the new lower working roll has been shifted from the center of the old lower working roll by an amount corresponding to 1/2 the difference in diameter between the new and old working rolls. The distance between the centers of the new upper and lower working rolls is greater than the distance between the old upper and lower working rolls by the sum of the difference in radius between the new and old upper working rolls and the difference in radius between the new and old lower working rolls. Generally, the upper and lower working rolls used in a pair are approximately equal in diameter. Based on the top surface of the lower backup roll, therefore, the center of the new lower working roll mounted in place has been vertically shifted from that of the old lower working roll by 1/2 the difference in diameter between the new and old lower working rolls. Similarly, the center of the new upper working roll has been vertically shifted from that of the old upper working roll by 3/2 times the difference in diameter between the new and old upper working rolls. The replacement of the working rolls involves such as definite relationship. However, conventional roll replacing apparatus are not provided with means for aligning new paper and lower working rolls with corresponding couplings respectively in accordance with this relationship and therefore involve great difficulties in replacing the working rolls.